It all started with a little rabbits.
On Christmas Day 1859, a shipment of 24 wild rabbits arrived in Melbourne, Australia. The animals were requested by English settler Thomas Austin, hoping to establish a rabbit population on his new Australian farm.
rabbits (Oryctolagus cuniculus) was caught around a family property in Baltonsboro, England, and taken to Austin’s home in Barron Park, Victoria.
Within three years, there were thousands of rabbits, and by 1865, Austin reported that he had killed 20,000 animals in his home.
Although there are stories of other people also importing fast-spreading animals to the continent, Austin was most likely the original source of the invasive rabbit plague in Australia, according to a new study.
“The biological rabbit invasion of Australia is one of the most famous invasions in recorded history, with devastating economic and environmental consequences,” lead author Joel Alves, a researcher at the University of Oxford, tells Treehugger.
“Our main motivation was to use genetics to trace the origin of this invasion, see how it matches historical records, and ultimately find out what made it so successful.”
spread and flourish
For their study, researchers analyzed the genetics of 187 European rabbits collected in Australia. Tasmania, New Zealand, France and Britain.
“We used whole-exome sequencing, which in simple terms means we sequenced all the rabbit genes. Then we performed several genetic analyzes of rabbits across Australia, explains Alves.
They found that most rabbits were closely related and expanded from Victoria, suggesting one major precursor. They also discovered that Australian rabbits are closely related to rabbits from southwest England.
The pattern they found matches the historical record describing the introduction of hares in 1859 to the Austin Homestead.
“Contrary to the many introductions to domestic rabbits that occurred before this, Thomas Austin’s rabbits were wild and likely better adapted to the wild environment,” Alves says. “We argue that this was the main aspect of their success.”
Previous reports of rabbits in Australia have mentioned traits such as floppy ears, softness, and luxurious coat colours. These are characteristics that are not usually seen in hares. But these populations either did not thrive or failed to spread beyond their original range.
However, Austin’s rabbits didn’t have those traits, and they were the ones who proliferated and thrived.
The results were published in the journal Proceedings of the National Academy of Sciences (PNAS).
disruption of the ecosystem
Invasive rabbits have had a serious impact on the ecosystem in Australia and could have severe consequences for biodiversity.
There are currently an estimated 200 million rabbits in Australia, according to Rabbit-Free Australia, a group that works to educate people about and eliminate feral rabbits.
“They compete with native species for a variety of resources, and cause overgrazing that prevents the regeneration of native animals and can cause desertification; their large numbers disrupt ecosystems and food waterfalls,” Alves says.
“Understanding what makes a biological invasion successful is a key aspect of developing mitigation policies that prevent the spread Invasive species. ”
The study found that despite many rabbit introductions that have been recorded over seven decades in Australia, most have failed. This was most likely because they were local and unable to adapt to the landscape.
“All that until the arrival of the wild rabbits,” Alves says. Many aspects contribute to species becoming invasive, and our study highlights how genetics can play a major role in this process. It also provides an additional mechanism for why there is a gap between the initial introductions and subsequent invasions.”
Today, Alves says, rabbits are “a kind of conservation paradox.”
“At most of the introduced sites, this pest is a very difficult pest to eradicate,” he says. “However, in its native habitat on the Iberian Peninsula, it is highly endangered despite being a primary species and with a critical ecological role.”
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